Globally, a large majority of HIV-1 infection in women occurs through heterosexual transmission (HST). HST transpires when semen (considered as the principal source for both cell-free (cf) and cell-associated (ca) virus) from an infected male interacts with the female genital mucosa (FGM). Recently, a seminal peptide, denominated as prostatic acid phosphatase (PAP), has been identified as a novel player in HIV-1 transmission and infection. The physiological function of PAP is not well understood but has been associated with both fertility and the sperm's motility. Recent studies have demonstrated that seminal amyloid fibrils (SAF) produced by seminal PAP have the ability to enhance the cf-HIV-1 infection by promoting the capture of the virus particles and the subsequent physical interaction of its host target cells in culture, but the role of SAF in ca-HIV-1 infection has not been studied. SAF possess an intrinsic positive charge that neutralizes the repulsive effect between HIV-1 and its target cells. The HIV-1 infection- enhancement effect of SAF has been demonstrated in vitro by infecting tissue culture cell lines and peripheral blood mononuclear cells (PBMCs) with cf HIV-1 requiring CCR5 and CXCR4 co-receptors. Interestingly, the effect of SAF has been observed to be more pronounced at low viral titers (resembling the in vivo HIV-1 titer in semen). Specifically, this study aims to investigate whether SAF enhances the transmission and infection of both cf and ca HIV-1 in FGM, and the role of female genital secretion (FGS) in this princess. The overall hypothesis of this study is that SAF enhances the transmission and infection of both cf and ca HIV-1 by promoting the physical attachment of the virus to FGM epithelia, thus increasing the subsequent access of the virus to the primary target cells in the stroma and that this process is direct or indirectly blocked or inhibited in the presence of FGS. To address this hypothesis, first we will determine, by using a cervical organ culture, whether cf and ca HIV-1 are transmitted across the FGM at different efficacies and the effect of SAF on the transmission process (Specific Aim 1). After it has been applied to a cervical organ culture, we will then determine whether SAF is present on luminal epithelial cells, or whether it has been incorporated inside the tissue;we will ascertain its effect on the HIV-1 infection of its primary target cells in the stroma (Specific Aim 2). Finally, we plan to determine the role of FGS in SAF activity during the transmission and subsequent infection of FGM with HIV-1 (Specific Aim 3). A better understanding of the role of SAF in HIV-1 infection and transmission within the FGM could lead to the development of new anti-HIV-1 HST-prevention strategies. PUBLIC HEALTH RELEVANCE: Through the proposed training, my goal under this fellowship is to complete my PhD at the same time that I get a strong and high qualified scientific expertise in the HIV-1 transmission and infection. This will positioned me as a competitive candidate at the moment of applying for a post-doctoral opportunity in this area. This training will also provide me with the necessary technical tools and practice that will help me develop as a success independent investigator on this field. With the help of this fellowship, the highly qualified laboratory and the broad expertise of my internal and external advisors I feel confident that I will have a successful and productive technical training at the same time that I will improve my writing, communication and reasoning skills. Specifically, my thesis project will contribute to a better understanding of the HIV-1 heterosexual transmission that eventually could be used in the development of more effective preventive strategies. Additionally, I will obtain knowledge and practices in some important and novel techniques such as the development of an organ cervical culture model to study the HIV-1 transmission and infection into the female genital mucosa, simultaneous immuno-phenotyping and in situ hybridization, tissue histology techniques as well as molecular techniques among others. Finally, I expect to publish at least two papers in addition to the three that I already have and present my findings in scientific meetings. [unreadable][unreadable]